Sewing machines having various mechanisms for delivering material to the sewing area under light tension are known in the art. An example of such mechanisms is shown in U.S. Pat. No. 2,754,114 issued July 10, 1956 to A. Weinkle et al. In this patent, the delivery of tape to the machine is dependent on the degree of tension on the tape in the area between the pull-off mechanism and the sewing machine. The drive motor in this patented device is continually switched on and off by means of a control element that scans the tape. In a second disclosed embodiment, an operably engagable clutch mechanism is arranged between the drive motor and the pull-off mechanism. In either embodiment, the mechanism is directly subjected to severe changes in sewing speeds and, as a result, the tensioning of the tape being fed to the machine is effected thereby. The named patent describes a third variant wherein a mechanical connection between the sewing machine and the pull-off mechanism is established. In this form, the pull-off mechanism operates according to the speed of the machine. Even with the transmission apparatus shown in this third variant, slippage of the workpiece and other negative influences affect the efficient operation of the apparatus.
U.S. Pat. No. 3,856,224 issued Dec. 24, 1974 to H. Van der Aa reveals a more recent attempt at a solution to industry's continued demand for an effective tape dispensing apparatus. This patented apparatus shows a motorized dispensing mechanism which is controlled by the amount of tape that is consumed in the sewing operation. Angular movement of a pivotal arm, adapted to ride in a tape loop, controls the feed rate of this apparatus. Yet, an apparatus, as described, which responds to rather than anticipates the use requirements of the receiving machine is not sufficient.